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MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTURE 



or stem motliers. These lay eggs early in the spring, and the young, 

 "which settle on the tender fir foliage and feed, later mature into 

 winged and wingless females. The wingless forms deposit eggs which 

 hatch later into females that atIII hibernate, while the winged females 

 migrate to the spruce and lay eggs at the base of the needles. The 

 young hatching from these cause the formation of the cone-shaped 

 galls. About the middle of July the forms in the galls become ma- 

 ture, full-grown, winged migrants Avhich return to the Douglas fir 



to lay eggs that also 

 produce hibernating 

 females. Altogether 

 there are five stages 

 or forms in which 

 these AdeJges appear 

 during different pe- 

 riods of their devel- 

 opment. 



The species is dis- 

 tributed from Brit- 

 ish Columbia to Cali- 

 fornia and eastward 

 into Idaho, Montana, 

 Wyoming, and Colo- 

 rado. 



Adelges oregonen- 

 sis Annand appears 

 as a small woolly 

 louse on the twigs 

 and base of needles 

 of larch in Oregon, 

 W a s h i n g t o n, and 

 ^Montana, but does 

 little damage. 



Adelges pic eae 

 Ratz. attacks the ter- 

 minal tAvigs of low- 

 land white fir and 

 noble fir and causes a 

 swelling to for m 

 around the bud, leaving it in a depression and making the twigs 

 appear to end in a solid knob. This causes the trees to become badly 

 gnarled. 



Adelges tsugae Annand may be found on the needles and bark of 

 western hemlock in California, Oregon, and British Columbia and 

 appears as white cottony tufts. 



The woolly pine louse {Pineus pinifoliae Fitch) {Chermes pini- 

 corticis Fitch {Chermes montanus Gill.) is found in the Xorthwest 

 from British Columbia to California and in Idaho, Montana, and 

 Colorado, where it attacks blue spruce, Engelmann spruce, Sitka 

 spruce, and western white pine. On spruce it forms loose terminal 

 cone-shaped galls somewhat similar to those of Adelges cooleyi, ex- 

 cept that the poorly formed chambers are intercommunicating and 



Figure 



:i. — Galls formed on Engelmann spruce by Cooley's 

 gall louse {Adelges cooleyi). 



